/*
    *  Licensed to the Apache Software Foundation (ASF) under one or more
    *  contributor license agreements.  See the NOTICE file distributed with
    *  this work for additional information regarding copyright ownership.
    *  The ASF licenses this file to You under the Apache License, Version 2.0
    *  (the "License"); you may not use this file except in compliance with
    *  the License.  You may obtain a copy of the License at
    *
    *      http://www.apache.org/licenses/LICENSE-2.0
   *
   *  Unless required by applicable law or agreed to in writing, software
   *  distributed under the License is distributed on an "AS IS" BASIS,
   *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   *  See the License for the specific language governing permissions and
   *  limitations under the License.
   */
  
  package org.apache.commons.daemon;
  
  import java.io.*;
  import java.net.*;
  import java.text.SimpleDateFormat;
  import java.util.Date;
  import java.util.Enumeration;
  import java.util.Vector;
  
  public class SimpleDaemon implements Daemon, Runnable, DaemonUserSignal {
  
      private ServerSocket server;
      private Thread thread;
      private DaemonController controller;
      private volatile boolean stopping;
      private String directory;
      private final Vector<Handler> handlers;
      private boolean softReloadSignalled;
  
      public SimpleDaemon() {
          System.err.println("SimpleDaemon: instance "+this.hashCode()+
                             " created");
          this.handlers = new Vector<>();
      }
  
      @Override
      protected void finalize() {
          System.err.println("SimpleDaemon: instance "+this.hashCode()+
                             " garbage collected");
      }
  
      /**
       * init and destroy were added in jakarta-tomcat-daemon.
       */
      @Override
      public void init(final DaemonContext context)
      throws Exception {
          System.err.println("SimpleDaemon: instance "+this.hashCode()+
                             " init");
  
          int port=1200;
  
          final String[] a = context.getArguments();
  
          if (a.length>0) {
              port=Integer.parseInt(a[0]);
          }
          if (a.length>1) {
              this.directory=a[1];
          } else {
              this.directory="/tmp";
          }
  
          /* Dump a message */
          System.err.println("SimpleDaemon: loading on port "+port);
  
          /* Set up this simple daemon */
          this.controller=context.getController();
          this.server=new ServerSocket(port);
          this.thread=new Thread(this);
      }
  
      @Override
      public void start() {
          /* Dump a message */
          System.err.println("SimpleDaemon: starting");
  
          /* Start */
          this.thread.start();
      }
  
      @Override
      public void stop()
      throws IOException, InterruptedException {
          /* Dump a message */
          System.err.println("SimpleDaemon: stopping");
  
          /* Close the ServerSocket. This will make our thread to terminate */
          this.stopping=true;
          this.server.close();
  
          /* Wait for the main thread to exit and dump a message */
         this.thread.join(5000);
         System.err.println("SimpleDaemon: stopped");
     }
 
     @Override
     public void destroy() {
         System.err.println("SimpleDaemon: instance "+this.hashCode()+
                            " destroy");
     }
 
     @Override
     public void run() {
         int number=0;
 
         System.err.println("SimpleDaemon: started acceptor loop");
         try {
             while(!this.stopping) {
                 checkForReload();
                 final Socket socket=this.server.accept();
                 checkForReload();
 
                 final Handler handler=new Handler(socket,this,this.controller);
                 handler.setConnectionNumber(number++);
                 handler.setDirectoryName(this.directory);
                 new Thread(handler).start();
             }
         } catch (final IOException e) {
             /* Don't dump any error message if we are stopping. A IOException
                is generated when the ServerSocket is closed in stop() */
             if (!this.stopping) {
                 e.printStackTrace(System.err);
             }
         }
 
         /* Terminate all handlers that at this point are still open */
         final Enumeration<Handler> openhandlers=this.handlers.elements();
         while (openhandlers.hasMoreElements()) {
             final Handler handler=openhandlers.nextElement();
             System.err.println("SimpleDaemon: dropping connection "+
                                handler.getConnectionNumber());
             handler.close();
         }
 
         System.err.println("SimpleDaemon: exiting acceptor loop");
     }
 
     @Override
     public void signal() {
         /* In this example we are using soft reload on
          * custom signal.
          */
         this.softReloadSignalled = true;
     }
 
     private void checkForReload() {
         if (this.softReloadSignalled) {
             System.err.println("SimpleDaemon: picked up reload, waiting for connections to finish...");
             while (!this.handlers.isEmpty()) {
                 // noop
             }
             System.err.println("SimpleDaemon: all connections have finished, pretending to reload");
             this.softReloadSignalled = false;
         }
     }
 
     protected void addHandler(final Handler handler) {
         synchronized (handler) {
             this.handlers.add(handler);
         }
     }
 
     protected void removeHandler(final Handler handler) {
         synchronized (handler) {
             this.handlers.remove(handler);
         }
     }
 
     public static class Handler implements Runnable {
 
         private final DaemonController controller;
         private final SimpleDaemon parent;
         private String directory;
         private final Socket socket;
         private int number;
 
         public Handler(final Socket s, final SimpleDaemon p, final DaemonController c) {
             this.socket=s;
             this.parent=p;
             this.controller=c;
         }
 
         @Override
         public void run() {
             this.parent.addHandler(this);
             System.err.println("SimpleDaemon: connection "+this.number+
                                " opened from "+this.socket.getInetAddress());
             try {
                 final InputStream in=this.socket.getInputStream();
                 final OutputStream out=this.socket.getOutputStream();
                 handle(in,out);
                 this.socket.close();
             } catch (final IOException e) {
                 e.printStackTrace(System.err);
             }
             System.err.println("SimpleDaemon: connection "+this.number+
                                " closed");
             this.parent.removeHandler(this);
         }
 
         public void close() {
             try {
                 this.socket.close();
             } catch (final IOException e) {
                 e.printStackTrace(System.err);
             }
         }
 
         public void setConnectionNumber(final int number) {
             this.number=number;
         }
 
         public int getConnectionNumber() {
             return this.number;
         }
 
         public void setDirectoryName(final String directory) {
             this.directory=directory;
         }
 
         public String getDirectoryName() {
             return this.directory;
         }
 
         public void log(final String name) throws IOException {
             try (final OutputStream file = new FileOutputStream(name, true); 
                  final PrintStream out = new PrintStream(file)) {
                 out.println(new SimpleDateFormat().format(new Date()));
             }
         }
 
         public void handle(final InputStream in, final OutputStream os) {
             final PrintStream out=new PrintStream(os);
 
             while(true) {
                 try {
                     /* If we don't have data in the System InputStream, we want
                        to ask to the user for an option. */
                     if (in.available()==0) {
                         out.println();
                         out.println("Please select one of the following:");
                         out.println("    1) Shutdown");
                         out.println("    2) Reload");
                         out.println("    3) Create a file");
                         out.println("    4) Disconnect");
                         out.println("    5) Soft reload");
                         out.print("Your choice: ");
                     }
 
                     /* Read an option from the client */
                     final int x=in.read();
 
                     switch (x) {
                         /* If the socket was closed, we simply return */
                         case -1:
                             return;
 
                         /* Attempt to shut down */
                         case '1':
                             out.println("Attempting a shutdown...");
                             try {
                                 this.controller.shutdown();
                             } catch (final IllegalStateException e) {
                                 out.println();
                                 out.println("Can't shutdown now");
                                 e.printStackTrace(out);
                             }
                             break;
 
                         /* Attempt to reload */
                         case '2':
                             out.println("Attempting a reload...");
                             try {
                                 this.controller.reload();
                             } catch (final IllegalStateException e) {
                                 out.println();
                                 out.println("Can't reload now");
                                 e.printStackTrace(out);
                             }
                             break;
 
                         /* Disconnect */
                         case '3':
                             final String name=this.getDirectoryName()+
                                         "/SimpleDaemon."+
                                         this.getConnectionNumber()+
                                         ".tmp";
                             try {
                                 this.log(name);
                                 out.println("File '"+name+"' created");
                             } catch (final IOException e) {
                                 e.printStackTrace(out);
                             }
                             break;
 
                         /* Disconnect */
                         case '4':
                             out.println("Disconnecting...");
                             return;
                         case '5':
                             out.println("Reloading configuration...");
                             this.parent.signal();
                             return;
 
                         /* Discard any carriage return / newline characters */
                         case '\r':
                         case '\n':
                             break;
 
                         /* We got something that we weren't supposed to get */
                         default:
                             out.println("Unknown option '"+(char)x+"'");
                             break;
 
                     }
 
                 /* If we get an IOException we return (disconnect) */
                 } catch (final IOException e) {
                     System.err.println("SimpleDaemon: IOException in "+
                                        "connection "+
                                        this.getConnectionNumber());
                     return;
                 }
             }
         }
     }
 }